Improving the assimilation part of the near real time system of IBI

Ocean forecast for the IBI (Iberian-Biscay-Ireland) region are provided in near real time within the framework of the Copernicus Marine Environment Monitoring Service (CMEMS). They are produced with a physical–biogeochemical coupled model over the north-east Atlantic Ocean from the Canary Islands to Iceland, including the North Sea and the western Mediterranean. 

The physical system, composed of a NEMO model at 1/36° resolution (around 2km, ORCA grid subset), has started operating in the early 2010s and continuously evolved with regular releases. Its ocean model is corrected through the assimilation of in-situ observations (T and S profiles) and satellite data (Sea Surface temperature, SST and altimetry) with the Assimilation System of Mercator (SAM) which is based on the SEEK Kalman filter. 

A CMEMS release is planned for 29th of November this year and a new version of the system will be operational. We will describe here the last evolution of the system focusing on the data assimilation updates. Changes in the model equivalent for the satellite Sea Level Anomaly (SLA) using a new formulation for the barotropic part leads to a better estimation of the innovation. The impact of this change and a discussion on the Mean Dynamic Topography (MDT) used will be developed.